A couple of pianos increase in value (8)

I believe the answer is:

appraise

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'value' is the definition.
(synonyms)

'a couple of pianos increase' is the wordplay.
'couple of' says to double the letters.
'pianos' becomes 'p' (this could be a standard abbreviation of which I'm unaware).
'increase' becomes 'raise' (raise can mean to increase or put up).
'p' doubled is 'pp'.
'a'+'pp'+'raise'='APPRAISE'

'in' acts as a link.

Can you help me to learn more?

(Other definitions for appraise that I've seen before include "Make assessment of value or quality" , "To gauge the worth" , "Evaluate or estimate" , "Decide the value or quality of" , "survey?" .)

I've seen this clue in The Telegraph.

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